If you don't get any of those in a run, then you can be happy and surprised. That's the easiest way to get through it. Also, people out gear the content so much now that it makes it much more difficult on new tanks (that mage hitting 500k+ right off the bat on a boss, blowing every cool down, and then promptly causing you to lose aggro).

At this point, unless you have Timeless Isle tanking gear, I wouldn't even think about attempting LFR. It would be far too frustrating.